Cartographer Calls for Elevation Markers in Flood-Prone Neighborhoods

RED HOOK — A Red Hook cartographer who moonlighted as a storm-chaser to map the flooding caused by Hurricane Sandy is now calling on the city to install elevation markers in flood-prone neighborhoods.

Jim McMahon, a mapmaker and writer for Scholastic, argues that elevation signs placed in low-lying areas would help residents determine when to evacuate ahead of future storms, and alert prospective homebuyers to potential flooding hazards.

"If they're predicting a storm surge of 13 feet, and people live at 2 feet, they can say, 'I better get out of here,' or at least move things out of the basement," McMahon told DNAinfo.com New York.

McMahon spent Oct. 29 — when the super storm blasted into the city — mapping the hurricane with John McGettrick, a longtime activist and fellow Red Hook resident who heads the Red Hook Civic Association. Together, they followed the flood waters as they stretched into the neighborhood, helping residents along the way.

"I ended up calling people to tell them to move their cars," McGettrick said. "We were looking around and seeing what we could preserve in the neighborhood."

By 8:45, as transformers and power lines exploded from the floodwaters, the pair decided it was time to go home.

"Initially, you're not thinking you're going to get killed — you don't think you're going to get killed in front of your own house," McMahon recounted. "Once I saw the electricity and water, the fourth-grade part of my brain kicked it: you need only a fourth-grade education to know that's a conduit to death."

As McGettrick described, "It was a little disconcerting."

Their research, however, yielded a map that showed that roughly 95 percent of Red Hook streets flooded, indicating, in part, that the neighborhood lies far closer to sea level than previously thought.

McMahon drew up the map and sent it to FEMA, which is redrawing the borders of the city's flood zones, as well as the office of Congresswoman Nydia Velazquez, whose district includes Red Hook. McMahon said he hopes the map, which is more detailed than those released so far by the city or publications such as The New York Times, will help officials better understand the potential consequences of, and better prepare for, future big storms.

"This was as a Category 1 hurricane," McMahon said. "A Category 2 or Category 3, all of Red Hook would be under water."

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